MCQ 11 Mark
The centroid of a triangle is (2, 7) and two of its vertices are (4, 8) and (-2, 6). The third vertex is
- A$(0,0)$
- B(4, 7)
- C(7, 7)
- D(7, 4)
Answer
View full question & answer→(b) (4, 7)
Explanation: Let A (4, 78) and B (-2, 6) be the given vertex. Let C(h, k) be the third vertex.
The centroid of $\triangle ABC$ is $\left(\frac{4-2+h}{3}, \frac{8+6+k}{3}\right)$
It is given that the centroid of triangle ABC is (2, 7) as obtained from above formula,
$\therefore \frac{4-2+h}{3}=2, \frac{8+6+k}{3}=7$
$\Rightarrow h=4, k=7$
Thus, the third vertex is $(4,7)$
Explanation: Let A (4, 78) and B (-2, 6) be the given vertex. Let C(h, k) be the third vertex.
The centroid of $\triangle ABC$ is $\left(\frac{4-2+h}{3}, \frac{8+6+k}{3}\right)$
It is given that the centroid of triangle ABC is (2, 7) as obtained from above formula,
$\therefore \frac{4-2+h}{3}=2, \frac{8+6+k}{3}=7$
$\Rightarrow h=4, k=7$
Thus, the third vertex is $(4,7)$